This invention relates in general to the servicing of electric motors used in the wheels of large automotive vehicles, and more particularly to a machine for extracting the electric motors from the spindles about which wheels of the vehicle revolve.
Some large off-the-road trucks of the type used at open pit mines are powered by diesel engines which drive generator sets which in turn are connected through heavy electrical cables to electric traction motors at the wheels of the vehicles. The electrical energy produced by the generators energizes the so-called motorized wheels, causing the wheels to turn and propel the vehicle.
The wheels themselves are quite large, having tires that in some instances measure in excess of 12 feet in diameter. The hubs of the wheels are likewise large and each revolves about a large spindle that is mounted on the chassis of the truck. The spindle houses the electric motor for the wheel, and the armature of the motor is connected to the wheel hub through a rather extensive gear train at the inboard end of the spindle. The motor alone may weigh as much as 6000 pounds.
The wheels and the spindle-housed motors which drive them are not easily serviced because of their size and weight. Moreover, the trucks themselves represent an extremely large capital investment, and must remain in operation as much as possible to justify the investment. Hence, many operators of these large off-the-road trucks prefer to replace an electric motor rather than attempt to repair the motor while it is on the truck, because replacement is usually less time consuming. Even so, the entire wheel must be removed to obtain access to the motor, and this in itself is a difficult and somewhat time consuming procedure.